Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

When the BCM receives a high beam headlamp OFF command and the high beam headlamp relay control circuit is shorted to ground.
When the BCM receives a high beam headlamp ON command and the high beam headlamp relay control circuit is shorted to voltage or open.
When the high beam relay coil side is open or the battery positive voltage to the high beam relay is open.